The sweet rice flour may be difficult to find if not shopping in oriental stores. Bob's Red Mill does put it out. May check a store that carries that product. Your Goya will work though. No need to add extra sugar. It will give you a chance to compare later on.
The difference in the salts mainly is the coarseness. Canning salt is very fine(dissolves quickly). Kosher is a coarser salt mainly used in cooking. Sea salt may be of any coarseness and color and contains more minerals. Two things to remember here. Always use non iodized salt when fermenting as the iodine in the salt will kill the beneficial bacteria we are after. Rather than measuring salt by volume measure by weight. This way the salt content will be constant regardless of type of salt. A half cup of canning salt weighs 134 g. If you have no scales and are using Kosher, round your half cup, you will be close.
What ever red pepper you are using. Add a little at a time and adjust to your taste when making the paste. You will be just fine.
Any more questions, please ask.
Tom